1. Field of the Invention
The invention relates to a rowing exerciser, and specifically to one that utilizes an adjustable magnet-controlled wheel mechanism which permits the user to adjust exercise resistance.
2. Description of the Prior Art
As shown in FIG. 9, in a conventional rowing exerciser the user sits on a slider 10 and uses both hands to pull a bar 11, bar 11 strains a cord 12 connected to it, cord 12 in turn extracts the shaft of a spring air-pressure cylinder 13 at its other end, and spring air-pressure cylinder 13 then generates appropriate resistance for exercise. When the user releases the strain, the spring reacts to put cord 12 and the bar 11 back to their original positions, so that the user can repeat the pulling exercise.
When the user would like to adjust the resistance for exercise, the valve on the spring air-pressure cylinder 13 must be turned. The resistance can be determined by the amount of fluid leakage. In other words, a large resistance requires less leakage, while a smaller resistance requires more leakage. However, the spring in the spring air-pressure cylinder 13 is apt to fatigue as a result of long term repeated stretching and reduces the exercise effects. At the same time, the spring air-pressure cylinder 13 is generally positioned under the exerciser, which causes inconvenience for adjustment.
Beside those rowing exercisers that utilize a spring air-pressure cylinder 13 for exercise resistance and cord restoration, there are ones based on an air-resistance or a user-weight mechanism design. The air-resistance fan mechanism 14 shown in FIG. 10 generates tremendous noise. Moreover, the user-weight mechanism 15 shown in FIG. 11 utilizes the weight of the user as the source of resistance, which can overburden the user.